CV-51002
2015.12.04
35
Transmitter Pre-Emphasis Levels
Exception for PCIe Gen2 design:
•
VOD setting = 50 and pre-emphasis setting = 22 are allowed for PCIe Gen2 design with transmit de-emphasis –6dB setting (pipe_txdeemp =
1’b0) using Altera PCIe Hard IP and PIPE IP cores.
•
VOD setting = 50 and pre-emphasis setting = 12 are allowed for PCIe Gen2 design with transmit de-emphasis –3.5dB setting (pipe_txdeemp =
1’b1) using Altera PCIe Hard IP and PIPE IP cores.
For example, when VOD = 800 mV, the corresponding VOD value setting is 40. The following conditions show that the 1st post tap pre-emphasis
setting = 2 is valid:
•
•
•
|B| + |C| ≤ 60→ 40 + 2 = 42
|B| – |C| > 5→ 40 – 2 = 38
(VMAX/VMIN – 1)% < 600%→ (42/38 – 1)% = 10.52%
To predict the pre-emphasis level for your specific data rate and pattern, run simulations using the Cyclone V HSSI HSPICE models.
Table 27: Transmitter Pre-Emphasis Levels for Cyclone V Devices
Quartus Prime 1st
Post Tap Pre-
Emphasis Setting
Quartus Prime VOD Setting
Unit
10 (200 mV)
20 (400 mV)
30 (600 mV)
35 (700 mV)
40 (800 mV)
45 (900 mV) 50 (1000 mV)
0
1
0
0
0
0
0
0
0
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
dB
1.97
3.58
5.35
7.27
—
0.88
1.67
2.48
3.31
4.19
5.08
5.99
6.92
7.92
9.04
10.2
0.43
0.95
1.49
2
0.32
0.76
1.2
0.24
0.61
1
0.19
0.5
0.13
0.41
0.69
0.96
1.26
1.56
1.87
2.11
2.46
2.77
—
2
3
0.83
1.14
1.49
1.83
2.18
2.48
2.87
3.23
3.61
4
1.63
2.1
1.36
1.76
2.17
2.58
2.93
3.38
3.79
4.23
5
2.55
3.11
3.71
4.22
4.86
5.46
6.09
6
—
2.56
3.06
3.47
4
7
—
8
—
9
—
10
11
—
4.51
5.01
—
Cyclone V Device Datasheet
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